Fifty years after it enrolled its first medical students, UC San Diego is crackling with optimism, having created one of the country’s most respected medical schools in a comparatively short period of time.

US News and World Report says the medical school is among the 20 best in the country in research and primary care — rankings partly based on the university’s history of developing drugs and treating cancer patients.

The magazine also points to UC San Diego’s exclusivity. The medical school accepts 3 percent of its applicants, making it nearly as hard to get into as the far older programs at Stanford and Georgetown.

The school’s 5,011 alumni include Margaret Allen, the first woman surgeon to perform a heart transplant, and Brian Druker, who helped develop the powerful cancer drug Gleevec.

The research-heavy medical school also has become the linchpin for UC San Diego Health, whose network of hospitals, clinics and treatment centers are currently running 1,600 clinical trials and studies that involve almost 35,000 participants.

“The growth of the UC San Diego medical school has been nothing short of remarkable,” said Dr. John Prescott, chief academic officer of the American Association for Medical Colleges (AAMC) in Washington, D.C.

“It’s happened because they’ve had a clear focus, a mission, and stable leadership. And a lot of their graduates want to stay in the area and practice. That says a lot.”

The medical school is turning 50 at the same time the university is wrapping up a $1.6 billion expansion in the health sciences. The boom created everything from Jacobs Medical Center to one of the largest centers in the western U.S. for translational medicine, the effort to speed up the creation of new drugs and therapies.

The university is now preparing to create a School of Public Health, and it is penciling out the construction of a replacement hospital in Hillcrest that will be devoted to clinical care and teaching.

Even bigger news may be in the offing: Dr. David Brenner, the med school’s dean, is hunting for someone willing to give $300 million in return for naming the school.

It would be the largest single gift that a donor has ever made in San Diego County, and one of the largest of its kind in academia.

“Comparable schools have been getting $250 million,” said Brenner, who is also vice chancellor of health sciences.

“I’d be happy with $300 million. That would be transformational.”

Ideally, he is looking for a donor who is widely known to the public, which would raise the medical school’s visibility. It’s been done before; UCLA named its medical school after David Geffen in 2002 after the entertainment mogul gave the program $200 million.

Brenner has offered little detail about how the $300 million would be spent, other than to say he wants to teach doctors to interpret and apply genetic data, and use mentors to cultivate more compassionate physicians.

But the school’s overall needs are well known.

The university often talks about the expense of operating a medical school. UC San Diego competes with the likes of Harvard, Columbia and the University of Pennsylvania for the best physicians and researchers. Recruiting a star researcher can easily cost $3 million to $5 million. And the university has to pay millions to help underwrite the education of medical students.

UC San Diego also faces a lot of societal pressures.

The nation’s population growth has slowed to a crawl. But life expectancy in the U.S. has risen by about eight years since the medical school opened in the 1960s. So there are ever-more older people who need medical care. And many of those people depend on academic medical centers.

The demand comes during an emerging physician shortage. The AAMC estimates that the shortage will reach 46,000 to 90,000 by 2025.

UC San Diego does not plan to train more doctors. But its been changing how its trains physicians in hopes of making them better, and more efficient. There’s also a need to cope with the changes brought on by extraordinary advances in medicine, particularly in tailoring treatment to a person’s genetic make-up.

The past seems crude by comparison.

When UC San Diego enrolled its first med students in 1968, the training of physicians was tied to “See one, do one, teach one.”

A student would see a procedure done, then do the procedure, then teach the procedure to another student.

“Today, we allow everyone to advance at their own speed, and they can practice as much as they want on a simulator,” Brenner said. “The simulations back then were so primitive you couldn’t really use them.”

The shift has been guided by physicians like Maria Savoia and Jess Mandel, who also press the need for problem-solving and team work.

“We’ve changed to much more active learning, in small groups, with fewer lectures and more situations where the students work things out for themselves,” Savoia said. “This is the way that things stick in your head.”

The culture has changed, too. There’s less paternalism.

“Physicians really view their role as working in partnership with the patient,” Mandel said. “And they collaborate with healthcare providers, other doctors, nurses.

“No matter how smart you are, no matter how well trained you may be, you need help in terms of getting your patient everything they need.”